This project is designed to investigate the behavior of individual neurons in the motor-sensory cortex and supplementary motor area during the production of spontaneous or operantly conditioned limb movements in awake, minimally restrained animals. Long-term chronic recordings from single cortical neurons are obtained with special microelectrodes. The location and coding properties of cortical neurons as they relate to various types of limb movement are being investigated. Microstimulation through the electrodes is used to map the output properties of the region of cortex under study. Sensory input is also examined for each neuron by passive manipulation and tactile stimulation.